The present invention relates to a process for printing ID cards using a thermal dye sublimation process and the ID cards produced thereby. More specifically, the present invention relates to a process whereby a thermal dye sublimation printing process is used for microprinting security features having a high degree of accuracy and pixel registration onto ID cards.
In the prior art, many different forms of ID cards include different types of security microprinting using certain words in the background of the ID. This is also a common feature on US and other foreign currencies and other forms of negotiable paper such as certified checks. In general, the microprinting appears as a kind of watermark on the background of the ID or may be imbedded into a shape contained on the ID card. For example, the Commonwealth of Massachusetts may microprint “Commonwealth of Massachusetts Official Document” across the entire background of the card in a diagonal pattern. Another example is the pattern placed in the background of a certified check that appears as the word void if the check is electronically scanned or copied. Typically, printing of this type is placed on the raw card stock itself when the raw stock is made and shipped to the issuing authority where the personalized information is printed onto the card at the card issuance location. In general, therefore, the microprinting is provided on the blank card stock when the card stock is received at the card issuance location.
The difficulty with applying this type of microprinting as described in the prior art is that it is typically completed using a single pass operation of black ink. While single pass printing is very clear and readable, it is also easily repeatable using most thermal printing technologies available on the market today. As a result, it is easy for counterfeiters to reproduce the microprinting security feature onto raw card stock and then apply the personalized ID information onto the card in a separate operation, thereby circumventing the security of the card. The other issue is that since the micro printing is placed onto the card stock at the point of manufacture, it is possible for a counterfeiter to obtain raw stock as the material passes through various warehousing, shipping and storage operations. In this manner, it is easy for a counterfeiter to create fraudulent ID cards simply by printing the desired personal information onto the raw cards that they obtain.
There is therefore a need for an identification card that includes a microprinted security feature that overcomes the above noted drawbacks while producing a card that is difficult to reproduce at a location other than the card issuance location. Specifically, there is a need for an ID card with a microprinted security feature that is applied at the time and place of the card issuance that cannot be easily reproduced using readily available imaging technology.